1. Field of the Invention
The present invention relates to a stringed instrument, particularly to a stringed instrument including a brace bar which is attached to a top plate inner surface of the stringed instrument such as an acoustic guitar, has a function of strengthening and supporting a body of the stringed instrument, and can adjust sounds by vibration of the top plate.
2. Description of Related Art
Conventionally, stringed instruments such as a guitar capable of producing unique tone to each stringed instrument by resonating vibration of tightly stretched strings in a hollow body and vibrating a top plate, are manufactured. Here, a general guitar is explained as an example. The guitar mainly includes a body formed into a hollow state with a top plate, side plates, and a back plate, a neck provided so as to be projected upward from the body, a fingerboard bonded to an upper surface of the neck, abridge provided at a center of a top plate outer surface of the body, a plurality of brace bars provided at a top plate inner surface for strengthening the top plate, a head provided at the distal end of the neck and a plurality of strings (for example, typically six strings in a case of a guitar) tightly stretched between the bridge and the head, as main components.
The plurality of brace bars attached to the top plate inner surface of the body have a function of strengthening the top plate, as described above. It is also known that layout, length, material, shape and the like of the brace bars have a great influence on sound characteristics such as sound intensity, tone, or resonation of the stringed instrument. For this reason, manufacturers of the stringed instrument pay close attention to attachment, layout, and the like of the brace bars.
Each brace bar is typically formed of a bar-shaped member obtained by processing woods, or the like. Such brace bar has at least one flat surface so as to be fixed to the top plate inner surface of the flat top plate in a tightly attached manner. Then, the brace bar is bonded to the top plate by applying adhesive to the above flat surface. The adhesive is typically used for manufacturing the stringed instrument. As a generally known layout of the plurality of brace bars, the brace bars are arranged from the lower side of a sound hole arranged so as to penetrate through the center of the top plate to the bottom edge of the body in a fan-like form. Attempts that each of length, shape, material, and the like of each brace bar is changed between a high-pitched tone region and a low-pitched tone region are made.
In addition, layout of the brace bars is not limited to the above layout in which the plurality of brace bars are simply arranged in a fan-like form, and it is known that long and short brace bars are arranged longitudinally and transversely, respectively, so as to improve sound characteristics (for example, see Patent Document 1). In addition, it is also known that both ends of each brace bar are processed to be tilted from the distal ends to the vicinity of the center, and the tilt angle is adjusted in accordance with arrangement of the top plate.
[Patent Document 1] Japanese Patent No. 3847746
However, the stringed instrument such as the guitar as described above is manufactured by bonding the brace bar to the top plate such that the entire brace bar is closely attached along the top plate inner surface. And the top plate is vibrated averagely over the entire plate. That is to say, there has been no stringed instrument having a configuration in which a specific spot of the top plate is intensively vibrated in the past.
As is well known conventionally, sound generated from one generation source propagates around the generation source as wave motion so as to strongly vibrate a specific spot.